Machine Dynamics Practice Test: Torsional Vibrations — Flashcards

Torsional Vibrations topics include: Torsional vibrations of single, two and three rotor systems, torsionally equivalent shaft, isolation and transmissibility and geared system torsinal vibrations.

Torsional vibration is a type of vibration that involves the angular vibration of an object, usually a shaft, along its axis of rotation. It can be caused by time-alternating torques that are superimposed on the steady running speed of a rotating shaft. 

Torsional vibration can be measured by measuring the RPM of a shaft with a high number of pulses per revolution (PPR). 
It can be measured using:
A torsiograph
An encoder
A laser vibrometer
A strobe light
A telemetry system 

Torsional vibration can be controlled by:
Dissipating the torsional vibration (kinetic) energy into heat (thermo-elastic)
Using torsional vibration absorbers 

Torsional vibration is different from lateral vibration, which occurs in the radial direction, and axial vibration, which occurs along the shaft length.